Dobruja
Dobruja, or sometimes Dobrudja (Dobrogea in Romanian, Добруджа—transliterated Dobrudzha—in Bulgarian, Dobruca in Turkish), is the territory between the lower Danube river and the Black Sea, including the Danube Delta and the Romanian coast. It's divided between Northern Dobruja (Dobrogea), which belongs to Romania, and Southern Dobruja (in Romanian, Cadrilater), which belongs to Bulgaria.
The Romanian region of Dobrogea consists of the counties of Constanţa and Tulcea, with a combined area of 15,500 km² and a population of slightly over a million. Its principal cities are Constanţa, Tulcea, Medgidia, and Mangalia.
The Bulgarian region of Dobrudzha, which is divided between the administrative regions of Dobrich and Silistra, has a total area of 7,565 km², and a combined population of some 350,000 people.

History
Main article: History of Dobruja
In antiquity Dobruja was inhabited by Geto-Dacians, as well as by Celts. A number of Greek colonies were founded in the 7th and 6th centuries BC. In subsequent centuries, control of the region was held at various times by the Thracians, the Macedonians, the Scythians, the Getae-Dacians, and the Sarmatians. In 46 it was annexed by the Roman Empire as Scythia Minor, part of Moesia. To prevent mounted attacks from the north, the Romans constructed a double rampart from the Black Sea down to the Danube. Dobrogea fell at certains times under Byzantine, Bulgarian domination.
Dobruja was dominated by the Kipchak Turks from 1064 (Halil İnalcık) until the advent of the Ottoman Empire. By mid-1200s, the Turkic-Mongolian Golden Horde Empire extended its sway over Dobrugea. Mongol elite quickly became Turkified and Islamized. A missionary Turkish mystic from Anatolia, Sarı Saltuk visited Dobruja in 1261, with 40 Turkoman clans, and his tomb in Babadag (which was named after him) is still a place of pilgrimage for the Muslims.
After 1325 a local ruler in southern Dobruja, Balik/Balica, split from the declining Second Bulgarian Empire. His heir, despot Dobrotitsa/Dobrotici, extended his rule over all Dobruja, giving his name to the region. After 1389 the state came under the rulership of Mircea the Elder, ruler of Wallachia. The Ottomans conquered it in 1415 and controlled it until the late 19th century. During the 19th century, a large number of Crimean Tatars who were forcibly removed from Crimea emigrated to this Ottoman land.
In 1878 Romania received Northern Dobruja as compensation for ceding Southern Bessarabia to Russia, whereas Bulgaria received the smaller, southern part. In Northern Dobruja, most of the population was Romanian, but it included a Bulgarian enclave in the nortwest (around Babadag and Tulcea), as well as some scattered Turkish and Tatar people.
At the advice of the French envoy, the Treaty of Berlin awarded the "Mangalia strip" (the dark-orange area on the map) to Romania as well, since it contained a compact area of ethnic Romanians in its south-eastern corner. This area was basically a strip of land that extended inland from the Mangalia port up to the town of Silistra (which remained in Bulgaria due to a large Bulgarian population there). Subsequently Romania attempted at taking over the town of Silistra. A new international commission in 1879 allowed Romania to occupy the fort looking over the city, Arab Tabia, however not the city itself.
Bulgaria lost Southern Dobruja to Romania in 1913, after the Second Balkan War. With Romania's entry in WWI, on the side of France and Russia, the Central Powers occupied all of Dobrogea and gave the southern portion as well as the Mangalia strip to Bulgaria. This situation lasted only for a few years as Romania emerged victorious at the end of the war and regained its previous territories. Bulgaria, nevertheless, regained Southern Dobrogea(Cadrilater) in September 1940, during World War II, despite Romanian negotiators' insistance that Balcic and other towns should remain in Romania. As part of the Treaty of Craiova, the Romanian inhabitants (most of them being Aromanian refugee-settlers from Macedonia along with colonists from Wallachia and some Romanians indigenous to the region) were forced to leave the regained territory, while the Bulgarian minority in the north were in turn made to leave for Bulgaria. The 1940 borders were reaffirmed in the post-war treaties of 1947 and are in place even today( on the map the present border is depicted by the red line).
Area, population and cities
The entire Dobruja has an area of 23,100 km² and a population of rather more than 1.35 million, of which just over two-thirds of the former and nearly three-quarters of the latter lie in the Romanian part.
Major cities are Constanţa, Tulcea, Medgidia and Mangalia in Romania, and Dobrich and Silistra in Bulgaria.
Coat of Arms of Romania
Dobrogea is represented by dolphins in the Coat of Arms of Romania.